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authorMatthew Garrett <mjg@redhat.com>2012-05-11 12:08:28 +0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-05-12 04:07:02 +0400
commit54d3f8c63d6940966217b807972778fb17c3fa82 (patch)
treefc42b3ac4b41ed1cebfd50e494c87a986a021e39 /drivers/usb/core/usb-acpi.c
parentda0af6e78ef311d97754aa03e10eade82cc99e16 (diff)
downloadlinux-54d3f8c63d6940966217b807972778fb17c3fa82.tar.xz
usb: Set device removable state based on ACPI USB data
ACPI offers two methods that allow us to infer whether or not a USB port is removable. The _PLD method gives us information on whether the port is "user visible" or not. If that's not present then we can fall back to the _UPC method which tells us whether or not a port is connectable. Signed-off-by: Matthew Garrett <mjg@redhat.com> Signed-off-by: Lan Tianyu <tianyu.lan@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/core/usb-acpi.c')
-rw-r--r--drivers/usb/core/usb-acpi.c57
1 files changed, 57 insertions, 0 deletions
diff --git a/drivers/usb/core/usb-acpi.c b/drivers/usb/core/usb-acpi.c
index cab5cb7c256c..8947b203d5a4 100644
--- a/drivers/usb/core/usb-acpi.c
+++ b/drivers/usb/core/usb-acpi.c
@@ -19,6 +19,54 @@
#include "usb.h"
+static int usb_acpi_check_upc(struct usb_device *udev, acpi_handle handle)
+{
+ acpi_status status;
+ struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+ union acpi_object *upc;
+ int ret = 0;
+
+ status = acpi_evaluate_object(handle, "_UPC", NULL, &buffer);
+
+ if (ACPI_FAILURE(status))
+ return -ENODEV;
+
+ upc = buffer.pointer;
+
+ if (!upc || (upc->type != ACPI_TYPE_PACKAGE)
+ || upc->package.count != 4) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ if (upc->package.elements[0].integer.value)
+ udev->removable = USB_DEVICE_REMOVABLE;
+ else
+ udev->removable = USB_DEVICE_FIXED;
+
+out:
+ kfree(upc);
+ return ret;
+}
+
+static int usb_acpi_check_pld(struct usb_device *udev, acpi_handle handle)
+{
+ acpi_status status;
+ struct acpi_pld pld;
+
+ status = acpi_get_physical_device_location(handle, &pld);
+
+ if (ACPI_FAILURE(status))
+ return -ENODEV;
+
+ if (pld.user_visible)
+ udev->removable = USB_DEVICE_REMOVABLE;
+ else
+ udev->removable = USB_DEVICE_FIXED;
+
+ return 0;
+}
+
static int usb_acpi_find_device(struct device *dev, acpi_handle *handle)
{
struct usb_device *udev;
@@ -40,6 +88,15 @@ static int usb_acpi_find_device(struct device *dev, acpi_handle *handle)
if (!*handle)
return -ENODEV;
+ /*
+ * PLD will tell us whether a port is removable to the user or
+ * not. If we don't get an answer from PLD (it's not present
+ * or it's malformed) then try to infer it from UPC. If a
+ * device isn't connectable then it's probably not removable.
+ */
+ if (usb_acpi_check_pld(udev, *handle) != 0)
+ usb_acpi_check_upc(udev, *handle);
+
return 0;
}